A narrative review: 3D bioprinting of cultured muscle meat and seafood products and its potential for the food industry

Abstract

The demand for meat and seafood products has been globally increasing for decades. To address the environmental, social, and economic impacts of this trend, there has been a surge in the development of three-dimensional (3D) food bioprinting technologies for lab-grown muscle food products and their analogues. This innovative approach is a sustainable solution to mitigate the environmental risks associated with climate change caused by the negative impacts of indiscriminative livestock production and industrial aquaculture. This review article explores the adoption of 3D bioprinting modalities to manufacture lab-grown muscle food products and their associated technologies, cells, and bioink formulations. Additionally, various processing techniques, governing the characteristics of bioprinted food products, nutritional compositions, and safety aspects as well as its relevant ethical and social considerations, were discussed. Although promising, further research and development is needed to meet standards and translate into several industrial areas, such as the food and renewable energy industries. In specific, optimization of animal cell culture conditions, development of serum-free media, and bioreactor design are essential to eliminate the risk factors but achieve the unique nutritional requirements and consumer acceptance. In short, the advancement of 3D bioprinting technologies holds great potential for transforming the food industry, but achieving widespread adoption will require continued innovation, rigorous research, and adherence to ethical standards to ensure safety, nutritional quality, and consumer acceptance.

1. Introduction

Food bioprinting is an emerging technique that can evolve the conventional food production and consumption by combining tissue engineering and food technology (Singh et al., 2024). This holds great potential to revolutionize the food production by mimicking the structural complexity and heterogeneity of natural meat via manufacturing systems devised in the tissue engineering field (Otto et al., 2016). For meat alternatives, lab-grown or plant-based meat offers more sustainable and ethically acceptable options than traditional livestock farming. To elaborate, food bioprinting utilizes three-dimensional (3D) bioprinting and various biological and synthetic materials derived from alternative sources to create edible products. By taking the benefits of 3D bioprinting, scientists are exploring the immense potential of lab-grown muscle food as a sustainable alternative to conventional animal agriculture and aquaculture (Y. Li et al., 2021; Barbosa et al., 2023).

Meat bioprinting encompasses the principles of additive manufacturing technology for edible products in a layer-by-layer manner. These 3D products should reconstitute the complex food architecture with a precise control over their architecture, texture, and nutritional content. Actual meat has heterogeneous fibrous structures aligned in a specific manner and connected to the tendons for contraction and relaxation. To meet anatomical intricacies, one of the feasible approaches of muscle food bioprinting is to bioprint living cells. For example, Kang et al. (2021) have successfully developed a steak-like engineered tissue by bioprinting three distinct types of bovine cells: muscle, fat, and vessel (Kang et al., 2021). Considering its early-development stage, relevant technologies are abruptly growing and will enable bioprinting plant -or animal- based cell types to create engineered meat with customized taste and texture.

The demand for alternative meat production is growing with increasing meat consumption, which is expected to be 72% higher in 2030 compared to 2000 (Fiala, 2008; Datar & Betti, 2010). This necessitates a shift from contemporary meat production methods that pose substantial environmental challenges. Similar to the risks created by land animals, it has been estimated that industrialized fishing has caused a reduction in ocean biomass content up to 80% (Rubio et al., 2019). Aquaculture seems capable of relieving the pressures of wild capture; however, carnivorous fish raised in aquaculture often rely on wild fish as a food source, which can also impact natural habitat (Naylor et al., 2000). With increasing food consumption in parallel to the increasing earth’s population, cell-based red meat or seafood can be a breakthrough.

The idea of edible 3D bioprinted muscle food products has drawn great interests and curiosity within many consumers and producers. Since the application of 3D bioprinting extend to the food sector, both opportunities and challenges are being recognized in various aspects. One of the key advantages of meat bioprinting is its potential to address sustainability concerns by minimizing the needs of livestock farming, including energy use, landing, water supply and feeding system (Dick et al., 2021). Recently, the environmental impact of traditional farming, including greenhouse gas emissions −15% of which are generated by livestock- and inadequate agricultural practices that contribute significantly to deforestation, biodiversity loss, and water pollution, has led to increased interest in alternative sources (Ramachandraiah, 2021). The ability to create customized meat products can conserve the massive resources required for livestock and overcome significant challenges address the confront obstacles (Godoi et al., 2016; Pereira et al., 2021).

Additionally, 3D bioprinted food can lessen food safety issues and offer a better quality-controlled environment. The precise control over the production process eliminates the possible addition of contaminants and reduce foodborne illnesses (Mcmenamin et al., 2014). However, prior to the adoption of 3D bioprinted muscle food, it is essential to consider customer acceptance and perception. Generally, consumers are open to the idea of the 3D bioprinted food, but there are still reservations and skepticism regarding its safety, taste, and overall quality (Manstan & McSweeney, 2019). Overcoming these concerns will require effective communication and education about the technology and its benefits. Another challenge is the scalability and cost-effectiveness of 3D bioprinted muscle food production. Currently, due to its early stage, the production process is relatively slow and expensive (Gross et al., 2014). Scaling up the production will require advancements in bioprinting speed and efficiency, as well as cost reduction strategies (Agunbiade et al., 2022). Overall, several challenges, including overcoming consumer skepticism, improving scalability and cost-effectiveness, and ensuring the safety and quality of 3D bioprinted muscle food, remain as key factors to fully realize the potential of this innovative technology.

The process of food bioprinting involves combining edible bioink formulations, typically composed of living cells obtained from animal biopsies or stem cell cultures, biomaterials, and growth factors with precision bioprinting techniques to create anatomically accurate muscle structures. The biofabricated constructs serve as a platform for cells to meticulously organize and mimic the intricate structure of natural meat. Meat bioprinting offers several key advantages, including significant reductions in environmental impact, decreased reliance on traditional livestock farming, and enhanced animal welfare in a controlled laboratory environment. By circumventing the resource-intensive practices associated with conventional meat production, including land use, water consumption, and greenhouse gas emissions, meat bioprinting presents a promising pathway towards sustainable food systems. Additionally, this technology has the potential to eliminate the need for intensive animal farming, thereby mitigating issues related to animal welfare and zoonotic disease transmission. Moreover, bioprinted constructs mimicking the native microenvironment and architecture of muscle tissue enable the investigation of complex biological processes, tissue regeneration, and cell-cell interactions.

The concept of meat bioprinting using animal biopsies represents a novel and innovative approach in the field of food technology. This cutting-edge technology encompasses various fabrication modalities and offers precise control over dimensions, heterogeneous deposition of biologics including biomaterials and cells, and nutritional contents. This review article covers these bioprinting modalities and the-state-of-art in relevant cells, biomaterials, printability, and nutritional values (Figure 1). Additionally, it aims to be one of the first studies to comprehensively discuss lab-grown meat products with a particular focus on the critical role of micro-nutritional content, including proteins, fats and carbohydrates. At last, the ethical implications and their translation to society along with opportunities for the future of tissue engineering and food production are discussed.

Figure 1.

An overview schematic of the 3D bioprinted cultured meat production process. A. Cell sourcing derived from livestock and aquaculture to obtain various cell types: B. Muscle and adipose tissue sampling. C. Muscle progenitor and adipose cells are isolated from tissue biopsies. D. Industrial scale bioreactors are used to cultivate and differentiate desired cell types. E. After cell maturation, bioink is prepared with edible ingredients. F. 3D Bioprinting with multiple nozzles for muscle and fat tissue separately. G. Bioreactors for 3D bioprinted meat cultivation and maturation. H. Customized bioprinted steaks and fish fillets (Figure was created with Biorender).

2. Bioprinting technologies for production of muscle food

The typical steps of muscle food bioprinting involve several key stages due to distinct and precise architecture of the skeletal muscle. The isolation and cultivation of animal cells initiate the process as they directly influence the desired final product depending on the cell source species.

The development of suitable bioinks is essential for bioprinting, which serves as the vehicle for delivering cells and other bioactive materials to the desired site (Gungor-Ozkerim et al., 2018). The bioprinting process usually utilizes cell-laden hydrogels as bioinks, which allows the controlled deposition to create 3D scaffolds with tailored architecture in predesigned spatial positions. Unlike traditional additive manufacturing techniques, the incorporated cells need to remain active during the bioprinting process to ensure successful tissue formation until the lab-grown meat is fully created then cooked. The main challenge for the material development is to apply edible bioinks with nutritional value besides biocompatibility (Guo et al., 2023). Following the completion of the primary stages of cell maturation and bioink development, the bioprinting process for the products of muscle food can be subsequently commenced.

2.1. 3D Bioprinting Techniques

Since its advent, bioprinting has been vigorously expanding its applications in biotechnology including muscle foods. Among various bioprinting modalities, extrusion-based bioprinting is considered as the most suitable methodology for generating fibrous meat filaments (C. Liu et al., 2018). It also offers high feasibility with a wide range of printable materials, contingent upon their extrudability via screw-based, syringe-based, or pneumatic-driven pressure (Figure 2). Screw-based extrusion utilizes an angular screw that continuously feeds, mixes, and dispenses the bioprinting materials via a motor. In this process, the bioink is loaded in a food cartridge with a wide opening on the top and moves downwards through a screw and narrower nozzle (Sun et al., 2018). It is suitable for minimal air entrapment but not compatible with materials with high-viscosity and tensile strength (Tibrewal et al., 2023). Meanwhile, syringe-based extrusion is performed by controlling the syringe plunger in a linear motion to directly push out the bioink. This process is suitable for highly viscous materials but is difficult to completely avoid air entrapment, causing inconsistent flows (Lipton et al., 2010). Furthermore, the process of refilling the cartridges is inconvenient and may vary the condition of air entrapment, leading to lower reproducibility. Pneumatic-driven extrusion is favorable for low-viscosity bioinks so is often not endorsed for meat bioprinting. Also, for industrial production, sterilization of air and prevention of air bubbles should be considered. Despite inherent challenges, some industrial applications have been reported using pneumatic-based extrusion (Godoi et al., 2016; Tan et al., 2018). indicating ongoing potential alongside the concurrent development of biomaterials and associated infrastructures.

Figure 2. Bioprinting strategies for muscle food production.

A. Extrusion-based bioprinting can be utilized with a screw-based, syringe-based, or pneumatic-driven mechanism, which dispenses bioinks into muscle fiber-like filaments via a narrow nozzle. Droplet-based bioprinting generates discontinuous droplets through the formation of air bubbles induced by heat or acoustic waves emanating from a piezoelectric actuator. Laser-assisted bioprinting forms droplets via a pulsed laser beam creating high-pressure bubbles on a bioink layer. Light-based bioprinting employs a laser source, such as UV or infrared radiation, to selectively cure photosensitive bioinks according to a digital mirror device enabled pattern. B. Quantitative assessment of bioprinting modalities regarding biocompatibility, precision, scalability, time efficiency, and cost efficiency (Yeo et al., 2023). Scores 1–3 represent low, medium, and high, respectively.

Droplet-based bioprinting (i.e., thermal or piezo-inkjet bioprinting as depicted in Figure 2A) enables the control of droplet volume and the depositing location with or without the incorporated cells. Unlike extrusion-based bioprinting, discontinuous droplets are generated with low-viscosity bioinks, which can require pre-established crosslinking methods (Murphy & Atala, 2014). Furthermore, there is a need to develop methods for integrating individual droplets, posing another challenge in forming a complete muscle food product. On the other hand, the small nozzle limits the cell concentration and bioprinting time, which eventually increase the chance of clogging within the nozzle, leading to frequent cleaning. Considering these factors, the prospects of droplet-based bioprinting for muscle foods are perceived to be not favorable.

Laser-assisted bioprinting uses a pulsed laser beam creating high-pressure bubbles on a laser-energy-absorbing (i.e., gold and titanium oxide) and a bioink layer with or without embedded cells (Figure 2A) (Kryou & Zergioti, 2022). The bubbles are formed into jets, which are then propelled toward a collector substrate, enabling the formation of pre-defined patterns with a resolution as fine as single-cell resolution (Barron et al., 2004). Also, since it is a nozzle-free technique, laser-assisted bioprinting can deliver cells at a high cell density without exposure to shear stress (Murphy & Atala, 2014). Nonetheless, the cost is high and limited scalability hampers high-volume production (Z. Wang et al., 2015). Additionally, although rare, bioprinted patterns may contain metallic residues, which will critically increase food safety consideration as scaling up. Hence, these concerns should be resolved for muscle food production.

For light-based bioprinting, stereolithography is a prevalent approach, which employs visible or ultraviolet (UV) light for selectively curing photosensitive polymers in an array of digital micro-mirrors (Figure 2A) (Kačarević et al., 2018; Kryou & Zergioti, 2022). This method has attracted attention for a nozzle-free process, high precision, and low cost. However, the use of light-blocking agents necessary for photoresist patterning has been restricted for muscle food production due to their carcinogenic and toxic nature (Levi et al., 2022). Further, potential detrimental effects of UV light on cells should be considered (Owida, 2022). Given this scenario, some studies proposed the ingenious adaptation of light-based bioprinting for muscle foods, such as the use of commercial food dyes as absorbers for stereolithography (Grigoryan et al., 2019) or the reconstruction of steak-type model using a photo-crosslinkable hydrogel via digital light processing, which is a type of light-based bioprinting (Jeong et al., 2022). As the potential use of light-based bioprinting has shown, it can open a new avenue for muscle food platforms.

Overall, extrusion-based bioprinting has demonstrated a number of experimental results, industrial applications, and commercial bioprinters owing to its high versatility, scalability, and cost-efficiency (Hospodiuk et al., 2017; Paxton et al., 2017; Fisch et al., 2020; X. Li et al., 2022; Sedigh et al., 2022). On the other hand, droplet-based or laser-assisted bioprinting has restrictions in large-scale reconstruction, while light-based bioprinting requires further validation for biocompatibility. In addition, extrusion-based bioprinting does not require chemical/rheological additives or a crosslinking process if bioprinted constructs can maintain mechanical stability. It is highly advantageous for muscle food production that a formula of bioprinted materials can be kept minimal, eliminating potential hazardous effects of additives. Also, it provides more capacity to investigate flavor profile. Taken together, while extrusion-based bioprinting stands as a simple, yet powerful, tool for developing muscle foods, other bioprinting modalities can be simultaneously developed to address obstacles. Along with bioprinting techniques, it is essential to explore cellular and material compatibility with extrusion-based bioprinting to fabricate desired muscle food products.

2.2. Cells

Several animal cell types have been proposed for lab-grown meat production. The choice of appropriate cell types for cultivation relies on their capacity for self-renewal and differentiation in an in-vitro culture with minimized animal-derived components (Shaikh et al., 2021). It is particularly important in the context of developing cell culture systems that are more defined and reproducible. Adult stem cells, muscle stem cells, somatic cells transformed into induced pluripotent stem cells (iPSC), and somatic cells trans-differentiated into muscle cells have been identified as promising sources for muscle food production. Moreover, adult muscle and muscle stem cells have been identified as commonly used sources for lab-grown meat considering their tissue origin. However, their proliferation capacity and senescence might be considered as their limitation for long-term culture. The successful derivation and long-term culture of embryonic stem cells (ESCs) in a serum-free medium were studied to show their high proliferation profile and the ability to differentiate into various cell types, indicating their suitability for culture in a setting with reduced animal-derived elements (Li et al., 2005). Similarly, the generation of iPSCs from adult somatic cells exhibited characteristics similar to ESCs, in which their differentiation potential could be modulated and determined in serum-reduced condition (Yanagimachi et al., 2013; Ghaedi & Niklason, 2016). However, these two cell types might raise ethical concerns due to their sources or generation process, such as causing immunogenesis, tumorigenesis or genetic modification.

The most common adult stem cells used in muscle food bioprinting are muscle satellite cells and mesenchymal stem cells (MSCs), such as adipose-derived stem cells, bone marrow stem cells, and fibro-adipogenic progenitors (Moghaddam et al., 2021; Reiss et al., 2021). The use of skeletal muscle cell precursors, myoblasts, and neural cells, in bioprinting skeletal muscle constructs has shown acceleration and restoration of the muscle tissue (J. H. Kim et al., 2020). The efficient myogenic/adipogenic differentiation of bovine fibroblasts in bioprinting has been also explored for steak-type cultured meat production (Jeong et al., 2022).

The process of obtaining desired cell types from a live animal through biopsies then expanding them in laboratory settings to produce enough cells is well established in the field of tissue engineering (Reiss et al., 2021; Jin & Bao, 2024). Once these cells are isolated, they are provided with necessary growth factors and nutrients either to encourage their proliferation or allow them to differentiate into desired cell types. The development of cell culture medium that supports the self-renewal and differentiation of stem cell types in the absence of animal-derived components has been a significant advancement for lab-grown meat in the cellular agriculture field (K.-H. Choi et al., 2020). This has paved the way for the scalable production of lab-grown meat that is not only environmentally friendly but also mitigating ethical concerns regarding animal use.

The first ever burger was made from 20,000 fibers grown from muscle stem cells at Maastricht University by Mark Post and his research team (Reiss et al., 2021). The muscle cells were extracted from cows to produce large-scale cell aggregates, taking 3 months to grow muscle cells into muscle fibers (Kools, 2019). Bioprinting technology has enabled the development of bioactive meat culture platforms to fasten this process. Live animal biopsies for meat analogues can also be isolated from bovine, pig or rabbit muscle and fat tissue. The first ever whole-cut steak was produced by Kang et al., 2021, where bovine satellite cells (bSCs) and adipose-derived stem cells (bADSCs) were used for cellular cultivation (Kang et al., 2021). The bSCs were isolated from masseter muscle of Japanese black cows and cultured until passage 3 (P3). After using cell sorting technique to obtain desired cell types (CD31⁻, CD45⁻, CD56⁺, CD29⁺, and Pax7⁺), bSCs were grown in 2D using fetal bovine serum (FBS) for efficient proliferation, then added with horse serum (HS) to induce differentiation into muscle cells. In another approach to develop stable cell populations, MyoD and PPAR_γ 2 genes were introduced into immortalized bovine embryonic fibroblasts (bEFs) to directly differentiate them into muscle and fat cells with appropriate portion of myogenesis and adipogenesis induction, respectively (Jeong et al., 2022). After growing muscle and fat cells with a desired ratio, myogenesis was induced for myotube formation for 6 days, followed by adipogenesis for 2 days. Jeong and their team successfully established a method for simultaneous fat accumulation in myotubes, which is an in vivo phenomenon for intramuscular fat formation (Jeong et al., 2022).

Similar approaches have been used for lab-grown seafood production. The isolation and characterization of certain cell types, such as piscine satellite cells (PSC), piscine adipose-derived stem cells (PASCs), fibroblast-like cells derived from fish fin, and skeletal muscle cells isolated from fish muscle tissue, have been the subject of recent research (Saad et al., 2022; Tsuruwaka & Shimada, 2022; E. Xu et al., 2023). PSCs are known for their efficient proliferative abilities but relatively low differentiation capacity into myotubes, while PASCs have been found to possess similar proliferative abilities and higher potential to differentiate into adipocytes (E. Xu et al., 2023). Satellite cells and ADSCs were isolated from the epaxial muscle of piscine species and transcriptomic analysis was used to improve the differentiation capacity of PSCs, achieving a 32% increase in differentiation by employing a combination of two inhibitor factors, transforming growth factor (TGF-β) and Notch signaling. Another approach commonly used for lab-grown seafood is to isolate fibroblast-like cells and differentiate them into various other cell types related to muscle formation (Tsuruwaka & Shimada, 2022). The study by Tsuruwaka and Shimada (2022) on fibroblast-like cell isolation from different piscine species examined the pluripotency of such cells for efficient differentiation, suggesting that cells derived from fish species might be more suitable for in vitro cultured meat due to their dynamically changing properties with a simpler treatment comparing to mammalian cells (Tsuruwaka & Shimada, 2022).

Seafood is one of the favorable choices as a protein source due to its taste and nutritional benefits. However, the nutritional richness of aquatic animals might be influenced by their culture environment. For instance, marine fish are known to have higher levels of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) compared to freshwater fish. Cell-based seafood has the potential to provide the nutritional value of produced fish muscle, with high protein and healthy fat content as well as essential minerals in a more stable form while avoiding life-threatening elements like mercury. This potential stems from the controlled in vitro environment in which lab-grown seafood is produced, allowing for precise manipulation of the nutritional content. Although lab-grown meat appears to be an excellent choice, one of the main limitations in its production is the lack of desired cell sources. While some cell lines have been previously isolated from various fish species, they have been commonly used for piscine toxicology studies (Rubio et al., 2019). Most of fish muscle cell lines have been isolated from zebrafish, Atlantic salmon, grass goldfish, and rainbow trout lacking myogenic potential, hindering muscle formation and function with limited growth capabilities, which make them poor candidates for long-term culture (Saad et al., 2022). According to a study, Atlantic mackerel was considered as a good alternative for cell isolation, which has high percentage of omega-3 fatty acids with their health benefits, and their population shows a downward trend in recent years (Monterey Bay Aquarium, 2022; Saad et al., 2022). The research group successfully isolated the cells from muscle biopsies of freshly caught fish and performed long-term subculture with over 130 times passages and high proliferative capabilities with simultaneous immortalization.

2.3. Bioinks and Their Printability

Developing cell-containing hydrogel bioinks and establishing the appropriate conditions for their printability are other key stages for muscle food bioprinting. The development of appropriate bioinks is crucial as they serve as carriers for cells and bioactive substances, influencing their cell activities and the accuracy of meat structure after bioprinting (H. Wang et al., 2023). One of the remaining challenges associated with muscle food bioprinting is the development of bioinks that can be edible and ensure the physiochemical requirements for their application according to the specific meat type. The bioprinting techniques of steak-like structures and fish-like structures are summarized in Figure 3.

Figure 3.

The schematic illustrations depict the processes and the designs of 3D bioprinted constructs. A. 3D design (left) of the steak-type cultured meat and a photograph of bioprinted steak-type cultured meat (right). The internal structure was composed of microchannels (Jeong et al., 2022). B. Engineered mold-cast marble-like constructs composed of bovine fat and muscle in a (i) ring and a (ii) semicircular configuration. The outer ring/left semi-circle is a lyophilized casted alginate-RGD plug onto which bovine satellite cells were seeded and myogenically differentiated into myotubes. The inner ring/right semi-circle is an alginate plug loaded with differentiated bone marrow stem cells (BMSCs). (iii) Marbled-like construct on a bioprinted scaffold composed of extracted mature adipocytes (differentiated BMSCs) within bovine engineered muscle tissue (Zagury et al., 2022). C. Schematic illustration of (i) the 3D bioprinting process. (ii) Digital photographs showing the bioprinting process within Pluronic bath (Reprinted (adapted) with permission from Ref. Dutta et al. 2022.Copyright (2022) ACS Applied Materials & Interfaces) (Dutta et al., 2022). D. Micro-CT images of native fish epaxial muscle. Blue: Intermuscular filler tissues; Orange: Muscle tissues; Muscle scaffold model was designed from simplified native muscle texture. Scale bar: 1 mm (E. Xu et al., 2023). E. The schematic of tendon-gel integrated bioprinting (TIP) for muscle, fat, and vascular tissue fabrication (Kang et al., 2021).

Biocompatibility refers to the ability of a material to perform with an appropriate cellular host response in a specific application (Williams, 1987). In the context of muscle food bioprinting, it should be ensured that bioprinted structures are not harmful to the surrounding cellular environment, highly biocompatible, and minimally cytotoxic. The bioink should support various cellular activities such as migration, proliferation, and differentiation to support appropriate cell functions (Chimene et al., 2016). Moreover, it has been previously studied that bioinks with high biocompatibility can be improved to have better printability, while enabling effective cell growth (Yin et al., 2018). These bioinks can be customized for specific meat options by incorporating edible multi-functional fillers, allowing the development of tissue constructs with high fidelity and microenvironments suitable for cell activities. Skeletal muscle-fat ratio is another well-known assessment metric for meat quality and juiciness. The predominant component of meat is often perceived to be muscle but certain varieties, such as Black cattle or Japanese Wagyu, have been reported as containing > 30% and ~ 50% fat, respectively (Gotoh et al., 2018). The intramuscular fat contents in beef steaks also differ according to the type of steak. There is only 10% and 47.5% adipose tissue in the ramp and sirloin of Wagyu beef, respectively (Kang et al., 2021). While the fatty acid composition of the muscle phospholipid and the concentrations of polyunsaturated fatty acids might vary based on the animal gender and fat content, the glycogen content of muscle tissue is related to the development of meat flavor (Woods & Fearon, 2009; Yao et al., 2019). Recently, Kang et al. and Jeong et al. showed promising results that enable controlling muscle-to-fat ratio (Figure 3A) (Kang et al., 2021; Jeong et al., 2022). However, cell viability and differentiation potential were prioritized while mostly non-edible ingredients such as Matrigel, fibrinogen or cattle and horse serum were involved in the bioink preparation process. These factors also allude to the challenges about different mechanical and structural properties of edible muscle and fat paste, which will eventually influence the printability, the viscoelastic behaviors, and the degree of texturization.

The printability of bioinks is another crucial element for successful fabrication of 3D structures, which is influenced by various properties, such as shear thinning and rheological behavior (Gopinathan & Noh, 2018). Physical properties of bioinks, including viscosity, elasticity, and yield stress, are particularly important for the 3D printability of meat products. These specifications play significant roles in determining their printability and the choice of nozzle size and pressure as shear stress may influence the growth and differentiation of cells (Balasubramanian et al., 2021). Desired physical properties of bioinks not only offer the maintenance of bioprinted structures over a long-term culture period (Figure 4A) but also myogenesis and adipogenesis occur more effectively in 3D than 2D (Kang et al., 2021; Y. Li et al., 2021). MacQueen et al. confirmed that scaffold microstructure promoted either cell aggregation or aligned muscle tissue formation but lacked the mature contractile architecture (MacQueen et al., 2019). Incorporation of nanocellulose and alginate in bioinks has been shown to offer a balance between shear-thinning properties and fast crosslinking ability, making them suitable for 3D bioprinting of living soft tissues with cells (Ianovici et al., 2022). The bioinks also need to exhibit sufficient yield stress and storage modulus to support the fidelity of scaffolds post 3D bioprinting × composition of muscle fibers, 3D bioprinting has great potential to generate scaffolds that will eventually become different cuts of meat (Reiss et al., 2021; Kumar et al., 2023). The assembly of muscle and adipose tissue including vasculature via using 3D bioprinting equipped with different printing heads has been demonstrated for the construction of steak-like meat, which can be considered an advanced method in lab-grown meat production (Zagury et al., 2022).

Figure 4.

Representative photographs of 3D bioprinted meat examples. A. The demonstration of structural integrity of the 3D construct with porcine skeletal muscle satellite cells and 4% GelMA-20% silk fibrin hydrogel at 0, 3, 7, 14, and 21 days (Y. Li et al., 2021). B. Photograph of 3D printed (i) circular zein/secalin scaffold utilized by electrohydrodynamic printing with mouse skeletal myoblasts (C2C12) and porcine skeletal muscle satellite cells (PSCs) to evaluate cell culture and differentiation conditions. Appearances of cultured porcine models (ii) without and (iii) with treatment by food colorant (Su et al., 2023). C. Preparation of cultured fat by 3D bioprinting. (i) Representative photographs of sodium alginate hydrogel, (ii) 3D bioprinted fat tissue cultured with porcine adipose progenitor cells after 10 days of differentiation, and (iii) porcine subcutaneous adipose tissue (pSAT) (Song et al., 2022). D. Photographs of 3D bioprinted steak-type cultured meat (1,2) in GelMA hydrogel with myogenic differentiated BEFS-teton-MyoD and adipogenic differentiated BEFS-PPARγ2 cells. The cross-section images (3, 4). Scale bar = 10 mm (Jeong et al., 2022). E. Representative images of 3D bioprinted and native tissue fillets of large yellow croaker. Piscine satellite cells (PSCs) and piscine adipose-derived stem cells (PADSCs) isolated from large yellow croaker to develop bioprinted fish fillets Scale bar, 5 mm (E. Xu et al., 2023). F. Optical images of the 3D bioprinted steak by assembling muscle, fat, and vascular tissues at (i) the top and (ii) cross-section view of the dotted-line area. Muscle and vascular tissue were stained with carmine (red color), but fat tissue was not. Scale bars, 2 mm (Kang et al., 2021).

Shape fidelity is one of the key factors of printability (P_r) to reconstruct the complex geometry of native muscle tissues. There are various methods to assess shape fidelity, such as diffusion rate (Zhou et al., 2021) and pore geometry (Habib et al., 2018) based evaluations. For this, bioprinted lattice structures are often used for analysis. The percentage of diffusion rate and printability are corelated and can be determined using Equations (1) and (2) as below:

$$D{f}_r=\frac{A_t-A_a}{A_t}\times 100\%$$ (1)

$$P_r=\frac{L^2}{16A_a}$$ (2)

where, A_t represents the theoretical area, A_a represents the actual area, and L represents the perimeter of a pore. In brief, a perfect square-shaped pore results in a 0% diffusion rate (i.e., A_t = A_a), which also gives the ideal P_r of 1. To elaborate, a P_r lower than 1 yields a rounded shape while a P_r higher than 1 yields an irregular shape. On the other hand, cellular alignment should be induced by topographical cues to mimic native muscle tissues. It has been an ongoing challenge to control topographical orientation within micro-scale filaments via bioprinting. To achieve this, several strategies have been investigated including 4D bioprinting (Miao et al., 2019) arranging micro/nanoparticles (W. Kim et al., 2019), pre- (W. Kim & Kim, 2020) and post-bioprinting (X. Chen et al., 2020) stimuli. However, in addition to geometric considerations, bioprinting strategies must satisfy fundamental requirements for cultured meat, such as edibility and the replication of meat analogs like texture, cost- and time-effectiveness.

Texture can be modulated based on material factors, including cell composition, biomaterial formulations, and mechanical properties (Cohen Ben-Arye et al., 2020). For instance, textured soybean protein-based material was utilized to replicate the texture of native bovine meat using different composition of cells (Cohen Ben-Arye et al., 2020). Briefly, co-culture of bSCs and bovine smooth muscle cells (bSMCs) and tri-culture with bovine endothelial cells (bECs) enhanced myogenic differentiation and extracellular matrix deposition. Typically, compared to native muscle, the bSC/bSMC combination revealed the same ultimate tensile strength, a meaty flavor, and a similar meaty texture when evaluated by volunteers. Although the approach was noteworthy for creating textured cell-based meat, it relied on cell seeding rather than bioprinting. However, modulating cell compositions and ratios is considered major factors (Hocquette et al., 2010), warranting further investigation with the use of bioprinting. For this, a cell-based meat comprising bSCs (42 fibers), bADSCs (28 fibers), and bECs (2 fibers) was developed (Kang et al., 2021). The ratio of cells and constructs reconstituted a real meat structure, which, when combined with tendon-gel-integrated bioprinting (Figure 3E), further mimicked tendon-meat composite tissues. In simple terms, tendon-like gel constructs were used as a physical support at both ends of the cell-embedded fibers. In addition, compressive modulus was similar between tendon-meat constructs and native muscle. However, bioprinting techniques have not yet achieved the desired flavor or nutrient profiles. All criteria, including texture, must be met to ensure a comprehensive approach for producing customer-oriented cultured meat.

Post-processing encompasses the culture of cell-based meat and cooking, which is closely related to texture. During fabrication, post-processing may be necessary to remove sacrificial constructs and to differentiate and mature tissue constructs (Figure 3C–3E) (Kang et al., 2021; Dutta et al., 2022). Specifically, cell culture media contain various supplements, some of which are extracted from animal sources. In addition to the in-vitro cultivation process, these supplements can cause additional psychological resistance. As an alternative approach, serum-free cultivation and the use of bioreactors are investigated to promote cell growth while minimizing the need for prolonged post-processing (Kulus et al., 2023). Furthermore, cooking methods can alter texture and flavor, which are influenced by a range of factors including dimensions. Along with post-processing conditions, the criteria of post-cooking could be investigated for comparison with native muscle, including cooking loss, shrinkage, moisture, and fat retention (Dick et al., 2021).

Ultimately, once bioprinting parameters are established, cost and time effectiveness are crucial, particularly for commercialization purposes. To begin with, the costs of bioprinters currently range from 5,000 to 200,000 USD (Sabzevari et al., 2023). Specifically, extrusion-based bioprinters offer a wide range of options, including economical models priced between 5,000 and 10,000 USD, and high-end models up to 1 million USD (Tong et al., 2021). The difference in costs arises from operability, such as resolution, crosslinking (i.e., photo- or thermal-crosslinking) capability, and biocompatibility. As such, droplet-based bioprinters are inexpensive and commercially available but do not support bioprinting of vital cells (T. Xu et al., 2005). Conversely, laser-based bioprinters are cytocompatible but are usually not readily available with a cost over a few hundred thousand USD (Sabzevari et al., 2023). Light-based bioprinters are reported to cost between $16,000 and $25,000 (Pérez Cortez et al., 2022) ugh this range can vary due to the presence of several subordinated modalities. Given the wide range of bioprinting parameters and operability, bioprinting modalities should be carefully developed and industrialized to optimize the production of cultured meat. In terms of time effectiveness, labor-related costs can be significantly reduced by around 28% through automated manufacturing processes (Garrison et al., 2022). However, scalability and processing time vary among different bioprinting modalities, highlighting the need to optimize the production of cultured meat accordingly. Considering all these factors, the potential in commercialization of bioprinting modalities was assessed regarding biocompatibility, precision, scalability, time and cost efficiency (Figure 2B). To date, extrusion-based bioprinting exhibits the most favorable characteristics. However, the development of edible biomaterials and large-scale production setups may significantly impact and alter this landscape.

3. Role of muscle food bioprinting on nutritional / food security

3.1. Protein and Amino acids

Muscle foods are regarded as important source of proteins (> 20%) making them popular amongst consumers (Cross et al., 2010; Laskowski et al., 2018). Amino acids are the chief constituent, which make up proteins and play a diverse role in human health. Proteins derived from muscle foods are labelled as complete proteins due to the presence of all essential amino acids. Also, the proteins derived from animal sources are known to have high biological value due to their higher digestibility. Anticipated growth in demand for muscle food (“Food and Agriculture Organisation (FAO) of the United States. Meat.,” 2021), driven by its desirable nutritional qualities, cannot be met due to the inability to raise output to match the demand levels. The increase in output can pose a threat to food security as is not sustainable (Post, 2018). Due to the disadvantages associated with livestock and concerns about animal welfare, bioprinting of muscle foods has received significant attention (Post, 2018).

Muscle stem cells derived from male piglets exhibited increased protein expression, when cultivated on a hydrogel, which enhanced their maturity ultimately resulting in improved yield of cultured meat (Y. Chen et al., 2023). Furthermore, when the amino acid profile of the cultured meat was conducted in comparison with pork, it was found that the amino acid content of cultured meat was lower (11.24%) in comparison with pork (21.89%). However, selective screening in glycine (2.53%) and proline (1.36%) contents revealed higher levels than traditional meat (Y. Chen et al., 2023). In specific, porcine muscle stem cells treated with ascorbic acid 2 phosphate resulted in significant improvements in amino acid (glutamic acid, glycine, arginine, proline, alanine, leucine, tyrosine, phenylalanine, lysine, aspartic acid, threonine, serine, valine, and histidine) production compared to the negative control sample (Zhu et al., 2022). A study reported that cultured chicken muscle tissues cultured at an optimal temperature 41 °C enhances the total amino acid composition (4.835 g/100 g) and increases the umami composition (C.-J. Kim et al., 2023). It was reported that proliferation and differentiation were improved at 41 °C, increasing the yield of amino acid content and the nutritional value of cultured meat. However, the amino acid content in cultured chicken muscles was lower than the natural chicken meat, necessitating further maturation to increase the amino acid content (C.-J. Kim et al., 2023). Recently Tanaka et al. (2022) developed cell-based meat using cell sheets (comprising bovine myoblast cells) on temperature responsive culture dishes (Tanaka et al., 2022). The produced meat exhibited protein denaturation with increased hardness after incubation, in which its protein content (6.3 %) was lower than that of beef (11.3 %) (Tanaka et al., 2022). The lower protein content was attributed to the higher water content in bovine myoblast cell sheets regardless of the cell culture period. Despite obstacles, myotubes improve the protein content (Gulve & Dice, 1989), which are essential as they contribute to the texture, protein quality, and maturity of the bioprinted products (Furuhashi et al., 2021; Guan et al., 2023).

Different processing conditions alter protein production in bioprinted seafood (Rubio et al., 2019). In detail, lower oxygen concentration in culture medium had detrimental impacts on protein production. Also, changes in pH affected protein production, where the temperature conditions influenced the protein production ability. Lower temperature (30 °C) was more suitable for protein production than higher temperature (37 °C) (Rubio et al., 2019). Considering the high cost involved in the production of bioprinted meat, scaffold-free cell powder meat was developed with lower serum content (B. Choi et al., 2023). Interestingly, the developed cell-based meat powder was rich in protein (~ 50%) content when compared to chicken (~ 30%) and beef (~ 25%). Nevertheless, texture-related considerations, including anatomical structure, the heterogeneity of cellular components, and practicality in culinary applications, should be considered.

There is limited information regarding the protein composition and quantity present in bioprinted meat, as the mainstream of research has been needed to yield nutritionally dense cells. The vast majority of research efforts have been focused on optimizing growth media to produce cells that are rich in nutrients. Considering the efforts, it is necessary to examine the impact of different growth media and scaffolds on the quality and characteristics of bioprinted meat and their impacts on human health (Luo et al., 2022; Broucke et al., 2023; Rao et al., 2023).

3.2. Lipids and fatty acids

Lipids and fats constitute indispensable components of the human diet. These entities are recognized for their ability to supply crucial fatty acids and transport vitamins that are soluble in fat. Muscle-derived food sources are widely recognized for their high content of omega-3 polyunsaturated fatty acids (Hathwar et al., 2010). Lipids and fatty acids are essential meat components that directly or indirectly contribute to its flavor and juiciness enhancing the palatability and consumer acceptability of food products (Miller, 2014; Carvajal & Mozuraityte, 2016). Lipids derived from muscle tissues contain a significant amount of unsaturated fatty acids, which exhibit notable anti-inflammatory properties and have the capacity to modulate oxidative stress levels (Calder & Grimble, 2002; Burnett et al., 2020). The utilization of bioprinting in meat production can modulate the fatty acid and lipid content by adjusting culture medium and growth conditions (Figure 4C and 4D) (Louis et al., 2023; Song et al., 2022; Zhu et al., 2022). Low initial fat content in bioprinted meat affects the sensorial quality, so high fat content is the major task (Broucke et al., 2023). In particular, enhancing fatty acids or their precursors can create nutritious meat products (Louis et al., 2023). Also, artificial bovine fat supports to mimic the function of both inter and intra muscular fat, exhibiting similarity to marbled meat (Figure 3B) (Zagury et al., 2022).

Bioprinting meat using a meat paste and lard augmented fat content in both raw (0.5–18.9%) and cooked (0.6–5.2%) samples (Dick, 2019). For instance, fibrous meat generated by a newly developed food bioprinter was high in monounsaturated (35.41 g/100 g) and polyunsaturated fatty acids (1.3 g/100 g) (C. Liu et al., 2018). Using a muscle to fat ratio of 1.7:1, cultured fish fillet samples resulted in similar textural quality (hardness: 5.4 N) to the native muscle sample, which took 17 days to develop into a native tissue-mimetic fiber arrangement (Figure 3D) (E. Xu et al., 2023). Considering the important role of fat in meat quality, bioprinted fat of porcine adipose progenitor cells (Figure 4C) was evaluated in comparison to porcine subcutaneous adipose tissues (Song et al., 2022). The findings highlighted that porcine adipose progenitor cells exhibited similarity with the fatty acid profile of porcine subcutaneous adipose tissue in terms of main components responsible for imparting typical pork (linoleic acid, oleic acid, and nonadecenoic acid) flavor. It was also reported that cultured fat, after differentiation for 10 days, exhibited a higher crude fat content compared to Day 0, thereby enhancing its resemblance to porcine subcutaneous adipose tissue (Figure 4C) (Song et al., 2022).

Seafood discards of fin tissue was utilized for bioprinting fish (Tsuruwaka & Shimada, 2022). A study on cell differentiation reported that culturing the cells resulted in the formation of adipocyte-like cells, characterized by the presence of white droplets, confirming the presence of white adipocytes. Upon characterization, these were found to be constituted of myristic acid (C 14:0), pentadecanoic acid (C 15:0), palmitic acid (C 16:0), palmitoleic acid (C 16:1), octadecanoic acid (C 18:0), oleic acid (C 18: 1n-9), linoleic acid (C 18:1n-6c), arachidonic acid (C 20:4n-6), and docosahexaenoic acid (C22:6n-3) (Tsuruwaka & Shimada, 2022). The fatty acid composition reported from bioprinted samples matched the fatty acid profile typically found in seafood.

Another study has been conducted on the use of fat from cultured meat to mimic the fat found in Wagyu beef. This was achieved by manipulating the fatty acid content, namely cis isomer oleic acid, in culture medium derived from adipose tissue in the cheek muscle of Japanese black cattle (Louis et al., 2023). Given the significance of fat, particularly the cis isomer oleic acid, in enhancing the sensory quality of Wagyu beef, the culture medium was supplemented with different free fatty acids. These included seven fatty acids (phytanic, pristanic, oleic, palmitoleic, myristoleic, erucic, and elaidic acids), six fatty acids (phytanic, pristanic, oleic, palmitoleic, myristoleic, and elaidic), and oleic acid alone. Cultured meat produced from the fatty acid enriched medium resulted in higher fatty acid composition (saturated fatty acid, monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA)) as compared to suet and cheek fat. The main factor responsible for flavor of the Wagyu beef, isomer oleic acid, was found to be significantly high in fatty acid cultured meat (Louis et al., 2023).

Based on the preceding discussion, it is evident that the nutritional makeup of bioprinted meat, specifically its protein and fat content, may be regulated by modifying the medium conditions during manufacturing. Furthermore, the desired composition of bioprinted meat can be maintained by carefully selecting and optimizing the bioink components that can closely mimic the taste, texture, and flavor of the conventional meat products (Chriki & Hocquette, 2020).

4. Safety issues of muscle foods bioprinting

Muscle foods are widely consumed based on their high nutritional composition, including proteins and lipids, and favorable sensory qualities. However, the dense nutritional value makes muscle foods prone to spoilage. Mainly muscle foods are spoiled by oxidation or microorganisms; wherein, oxidation is a degrading process responsible for generation of compounds that are toxic (Kubow, 1992; Soladoye et al., 2015). For example, oxidation is a degrading process, induced by several parameters responsible for spoilage of muscle foods and generation of compounds that are toxic to human health (Kubow, 1992; Soladoye et al., 2015). Muscle-derived food products have been associated with the transmission of various pathogenic microorganisms, including Aeromonas hydrophila, Campylobacter jejuni, Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica, Bacillus cereus, Clostridium botulinum, Klebsiella pneumonia, Pseudomonas aeruginosa, and Enterococcus faecalis (Pateiro et al., 2021; Kulawik et al., 2022). Additionally, these food products have been linked to the transmission of viruses such as hepatitis A and E, coronavirus, swine fever virus, influenza, sapovirus, adenovirus, and enterovirus (Kulawik et al., 2022). Furthermore, parasites such as Toxoplasma gondii, Neospora caninum, Sarcocystis spp., Cryptosporidium parvum, and Echinococcus granulosus have also been associated with these food products (Abuseir, 2021; Ahmed et al., 2021). These microorganisms, viruses, and parasites are known to cause diseases and infections in humans.

Bioprinting is widely recognized for its ability to improve food safety, particularly in muscle foods that are vulnerable to multiple hazards (Z. Bhat et al., 2015; Zimmerling & Chen, 2020; K. Handral et al., 2022). However, serious issues have been highlighted regarding safety concerns with the use of chemicals involved in fat production for bioprinting of muscle foods. Recent studies by Sugii et al. (2022) and Gu et al. (2022) highlighted the use of some harmful chemicals and pharma compounds involved in the production of fat and cultured medium (Gu et al., 2022; Sugii et al., 2022). Recent studies highlighting the use of some harmful chemicals (IBMX) and pharma (insulin, dexamethasone, rosiglitazone, penicillin) compounds involved in the production of fat and cultured medium (Gu et al., 2022; Sugii et al., 2022; Louis et al., 2023). Regulatory limits have been established for these substances. Also, in cases where serum is used for cell culture, rigorous assessment procedures should be implemented to ascertain for the presence of any infectious agent, allergens, and antibiotics, which are known as potential impediments to food safety (Sugii et al., 2022; Broucke et al., 2023). A recent finding by Song et al. (2023) quantified the production and residual accumulation of approved food additives and medical drugs in cultured fat (Song et al., 2023). The cultured fat was found to contain insulin (2.78 μg/kg), dexamethasone (8.78 μg/kg), isobutylmethylxanthine (13.92 μg/kg), rosiglitazone (41.43 μg/kg), and indomethacin (17.39 μg/kg), thereby raising concerns regarding food safety. The fat sample contained higher levels of insulin residues, which could be lowered (1.88 μg/kg) using phosphate buffered saline after 10 days. The study also highlighted that residues of medical drugs were present in fat till Day 10. As muscle food bioprinting is in its nascent stage, no such overview associated with the actual spoilage mechanism has been reported. However, when compared to the risks involved in traditional animal farming for meat production, muscle food bioprinting offers preventive measures. This is achieved by a sterile environment, adherence to strict processing conditions during production, and the careful selection of cells to prevent the development of antimicrobial resistance and maintain genetic stability. This issue is addressed for the research scale using appropriate sterile hoods, non-thermal technologies, antiseptic syringes, and sterilized biomaterials (J. H. Kim et al., 2020; Mao et al., 2020; Brunel et al., 2022). Additionally, cultured meat formulations incorporate suitable additives as a part of the production process (Z. F. Bhat et al., 2019; Broucke et al., 2023).

Giving the rising demand for bioprinted meat products, all the regulatory bodies have focused on overseeing the entire process starting from cell banking and collection for growth and differentiation, harvesting, production and labeling. Formulating new regulations for classifying the bioprinted meat under a novel food category. Detailed information on ingredients used, their origins, any residue of materials present, nutritional content and potential hazards are to be considered. Regulatory bodies, such as the United States Department of Agriculture (USDA), United States Food and Drug Administration (USFDA), European Food Safety Authority (EFSA), and Singapore Food Agency (SFA), have suggested several regulatory frameworks in the production of cultured meat (Sugii et al., 2022; U.S. FDA., 2018). Cultured meat is an innovative food production, necessitating meticulous selection of the ideal cell line and comprehensive understanding of its historical use, health effects, and production methods.

5. Ethical and Societal Consideration of Bioprinting Muscle Food

The paradox of the ship of Theseus has been under philosophical scrutiny for centuries with no resolution (Gallois, 2016). Bioprinted food may face the same scrutiny; the planks and nails that relate to the identity of the ship are now the fats and proteins of our future foods. As we have mentioned above bioprinting muscle food holds several promises, including environmental sustainability, and improved quality of life for humans and animals alike, yet it also raises important ethical and societal considerations.

5.1. Potential Benefits to the Environmental, Animals, and Humans

Similar to cultured meat, once cells are harvested, proteins and fats can be grown in a laboratory, which would reduce the environmental footprint compared to conventional livestock farming, by helping or eliminating the need for traditional animal farming. This approach would result in a reduction of methane emissions and reduction of the amount of land required for livestock (Mateti et al., 2022). With more renewable energy sources in the future, bioprinting food has the potential to produce significantly reduced carbon emissions (Dong et al., 2022). Bioprinted food also benefits the environment by having the ability to waste/recycle unused food as we could transform imperfect or unsold produce into a bioink for other high-value human food (Zhong et al., 2023).

As mentioned above, another potential benefit of bioprinted food is the ability to reduce zoonotic diseases, such as mad cow diseases, and foodborne illnesses that are passed from livestock to humans (Treich, 2021). Bioprinted muscle tissues could control for protein and fat content, which can enable more nutritional and healthier food in general, and potentially tailored to different individual’s dietary needs, such as including low potassium for a person with chronic kidney disease (Burke-Shyne et al., 2020; Tan et al., 2018). Similarly, it can be used to infuse food with medicinal products, which can help eliminate transportation and low-temperature refrigeration requirements (Taneja et al., 2022). In this regard, bioprinting muscle tissues hold several promises, including its use to push the boundaries of further space exploration, as it could provide an alternative way to produce food for long space missions (Carbajal Gamboa et al., 2022).

From a less anthropocentric view, the greatest benefit of bioprinting meat may be reduced or no harm to animals (Guo et al., 2023); in an ideal world, this could abolish factory farming and unnecessary slaughter of animals. Similarly, bioprinted food may also extend to seafood; research would suggest that bioprinting seafood, such as salmon, allows for more control over the texture, and creates a more comparable meat alternative (Tay et al., 2023). Additionally, it would allow for numerous health benefits, without the concern of consumption of potential toxins, such as mercury. The production of seafood would also alleviate a strain on current ecosystems, which would allow for increased biodiversity and decreased spread of diseases among aquatic life (Kazir & Livney, 2021).

However, it is important to consider the treatment of animals used in the development and testing of bioprinting technologies (e.g., harvesting of cells). Though still early in development, 3D bioprinted meat can be produced from plant-based sources. Companies, such as Novameat and Redefine, have created steak from only plant derivates. Other popular research is using soybean as the protein source of bioinks (Tibrewal et al., 2023), which would help mitigate concerns about animal harm.

5.2. Ethical and Societal Consideration of Bioprinting Muscle Tissue

Though bioprinting has many potential benefits, it is not exempt from drawbacks. From an environmental perspective, one must consider the sustainability of the materials and energy sources used in bioprinting processes. This is connected to considerations about how resources to develop and scale up bioprinted food products are allocated as well as considerations about the accessibility and affordability of such products. Currently, the initial investment to produce bioprinted muscle tissues as well as the serums are very costly, with equipment costs alone reaching around $5,000 (“What Is 3D-Printed Meat,” 2023). This results in high-cost products that only privileged individuals can access (e.g., £20–30 for a 3D printed steak in London) (Bryant, 2020). Another related consideration is the disruption of existing food supplies and economies, and the need to mitigate negative economic and social consequences from this.

There is also long-term health effects of consuming bioprinted meat that are not yet fully understood, as such further research to assess potential health risks and impacts is needed. Similarly, though bioprinted food may have less chance of carrying foodborne illness, during its production cycle, either due to the use of chemicals involved in fat production or as a result of not being handled carefully, may become unsafe for human consumption (Taneja et al., 2022). Thus, in order to protect consumers safety, standards and regulations around muscle food bioprinting need to be developed and rigorously enforced.

Under the current state of affairs, either new legislation will need to be created specific for bioprinted meat, or the definition of meat under current standards will need to change (Bryant, 2020). Bioprinted meat raises questions about what “real” meat is, and how this might change the future of food? (Guo et al., 2023). With such a technology, as an extreme example, human meat could be made for consumption. Though this example may be particularly extreme, it is one of the future moral hazards that may be created from bioprinted foods. Other considerations have to do with the processes involved. For example, if bioprinted meat is derived from cultured proteins and fats from animal cells this put it under a similar category to cultured meat. However, bioprinted muscle tissues are not limited to meat or animal sources, which complicates the definition more. Moreover, under the current regulatory framework government bodies, such as EFSA, USDA, and USFDA, may fail to protect consumers due to not having the logistics or the authority to oversee such engineered products.

Another key societal consideration is whether consumers will accept bioprinted muscle food. Public perception and preferences can significantly influence the adoption and success of this technology. Even if the bioprinted food was able to duplicate desired textures for muscle tissue (Treich, 2021), there might still be cultural and religious beliefs considerations for people to oppose consuming bioprinted muscle tissues. There have been a number of studies looking at consumer perceptions of cultured meat, which provide insights into perceptions around 3D printed meat. For example, some people have concerns similar to those raised for genetically engineered foods, as they see these products to be “not natural” or have specific religious beliefs, such as in the case of Judaism, Islam, Buddhism, and Hinduism, which have restrictions on the type of meat, or how it is obtained.

The systematic review by Kantono et al. 2022 analyzed 14 empirical studies, which highlighted demographic variations in consumer acceptance, factors influencing acceptance, including familiarity with the technology and culture (Kantono et al., 2022). Overall, a relatively small proportion of participants chose cultured meat over the conventional meat. A common perception across the reviewed studies was that cultured meat is unnatural, which was one of the key objections towards the consumption of cultured meat. This perception was linked to concerns about the safety of cultured meat and the belief that it is inherently unethical. Also, a number of studies reported consumers perceiving cultured meat less healthy and find it to have inferior taste, texture, and appearance compared to the conventional meat, which contributes to the rejection of cultured meat. Their study also found evidence of consumers’ societal concerns regarding the potential end of traditional animal farming, distrust of companies producing cultured meat, and the energy required for its production. Another study by Pakseresht et al., which reviewed factors affecting consumer acceptance of cultured meat, found that public awareness, perceived naturalness, and risk perception were the most important factors influencing acceptance or rejection (Pakseresht et al., 2022). The study identified a generally low level of acceptance.

Among the few studies on 3D bioprinted meat, one study reported an online discussion group with Australian participants (Lupton & Turner, 2018). While the participants recognized the potential benefits of bioprinted meat products for society, they perceived it as “unnatural,” with linking this perception to potential harm or even ethical concerns. This reflects a key concern found in cultured meat related studies in the context of consumer perceptions. Other perceptions included the lack of taste or less nutritious content of bioprinted meat products. The studies on consumer perceptions of cultured or bioprinted meat are consistent with research indicating that factors such as disgust, perceptions of naturalness, and healthiness are key determinants of willingness to try novel foods. One way to respect these views is by ensuring the transparent labeling of these products.

Considering the potential benefits and the potential risks raised by bioprinted muscle tissues (Table 1), it is essential for researchers, policymakers, industry and ethicists to work collaboratively to ensure clear ethical guidelines and regulations that promote the responsible and sustainable development and the use of bioprinted muscle tissue. Public engagement and transparency are also key to building trust and ensuring that bioprinted meat aligns with societal values and expectations.

Table 1:

Potential benefits and drawbacks of bioprinted food, focused on bioprinted cultured meat.

Benefits	Drawbacks
Reduced carbon emissions (Dong et al., 2022)	Lack of legislation and logistics of production (Bryant, 2020; Taneja et al., 2022)
Ability to recycle/reuse food (Zhong et al., 2023)	Effects on the economy, especially individuals that survive on farming (Bryant, 2020)
Less land is required to produce meat (Dong et al., 2022)	Complexity in meeting requirements for religious practices (Bryant, 2020)
Decreased risk of illness from food (Treich, 2021)	Potentially not attractive to consumers (Treich, 2021)
Healthier food overall (Burke-Shyne et al., 2020)	High startup cost (“What Is 3D-Printed Meat,” 2023)
Ability to control food for special diets (Tan et al., 2018)	Potential hazard of radical changes in food (Guo et al., 2023)
Improvement of medicine infused foods (Taneja et al., 2022)
Potential prolonged trips for astronauts (Carbajal Gamboa et al., 2022)
Potential of no harm caused to animals (Guo et al., 2023)

6. Economic Implications of Muscle Food Bioprinting

The economic implications of 3D bioprinting muscle food are multifaceted and have the potential to significantly impact various aspects of the food industry. This technology offers valuable advantages for meat and seafood production including personalized nutrition, broadening the available food materials, customized designs, and reducing potential toxicity and pathogen transmission risks (Z. Liu et al., 2017). However, muscle food bioprinting needs to be scalable and economically available to be a useful alternative for traditional meat and seafood industry. One of its major roles globally is providing an important source of animal protein, particularly for vulnerable communities considering supply chain challenges.

Several studies have researched the potential economic benefits and challenges associated with the production and acceptance of cultured meat. Some emphasized the social questions raised by cultured meat related to its economic impact on communities (Post et al., 2020), in which its success lies upon public perception and acceptance (Shaw & Mac Con Iomaire, 2019). Another study supported this idea in a systematic review on consumer acceptance of cultured meat and found that consumer perceptions of taste and the economic implications for the meat-packaging industry are significant factors influencing the adaptation of lab-grown meat (Bryant & Barnett, 2020). Furthermore, religious and social perceptions can be identified as risk factors including the potential job loss and ethical implications, which could have economic repercussions (Ho et al., 2023). On the other hand, constructive regulations and policies might signify the potential of economic growth within this sector. Noted that the cultured meat has received one of the first regulatory approvals to enter the market in Singapore, then the prices have dropped significantly, indicating a positive trajectory for this sector (Cornelissen & Piqueras-Fiszman, 2023).

Following gaining significant attention, lab-grown meat has been involved in the approval process for consumption in other countries, such as Israel and the United States (US) (Hiayev et al., 2023; Jin & Bao, 2024). These approvals mark significant milestones towards the commercialization of lab-grown meat products. In the context of the potential for each producer to create their own versions, such as crafted seafood, different meat types and charcuteries, it is important to consider the implications for diversity, competitiveness, and benefits of high-skilled job creation (Stephens et al., 2018). This approach aligns with the concept of the integration of traditional agriculture and aquaculture with new technologies that presents an opportunity to effectively establish a circular economy. Sustainability of the overall production process by utilizing waste products to minimize environmental impact and maximize resource utilization involves the broader trend of the economic implications of lab-grown meat and seafood products. This debate is still controversial. Proponents claim that this innovation has the potential to revolutionize the muscle food industry, with wide implications for the environment, health, and animal welfare (Treich, 2021). However, an opposing argument also needs to be considered that the process of producing muscle tissue in vitro may be costly and inefficient in terms of resource use, as a large amount of energy is required for cell culture and bioreactor operations (Yamanaka et al., 2023). The main argument related to the issue of in vitro growth of edible size muscle tissue is that comparing it with naturally evolved muscle tissue over a long period of time is not only inefficient but also costly in terms of environmental externalities (Treich, 2021). As there are no research to directly compare the production cost between traditional agriculture and lab-grown meat, Yamanaka and their team (2023) provide a low-cost serum-free media development methodology using microalgae derived nutrients as an alternative to serum-free media (Yamanaka et al., 2023). The use of any animal-derived serum, which provides essential growth factors during cell culture for in vitro meat production, raises concerns related to environmental impact, contamination risks from pathogens, and unstable supply with high costs. Additionally, nutrients derived from grains and heterotrophic microorganisms are used for some of the ingredients of basal medium that can be affected by climate change and can contribute environmental pollution due to the application of chemical fertilizers and pesticides (Okamoto et al., 2019). The challenges associated with high energy consumption in various systems and industries necessitate the urgent implementation of novel energy-efficient systems. All these challenges require huge amount of energy consumption, and a novel system needs to be urgently considered, such as having high growing capacity, usable protein content, and ability to aid in carbon neutrality to lower economic burden. More research needs to be conducted to explore the details in enabling the establishment of a true cost accounting structure to understand the financial impact of the circular economy.

Cultured meat production is anticipated to have a significant impact on the global meat industry, especially in major meat-exporting countries like the US, Brazil, the European Union, and Argentina (Dutra da Silva & Conte Junior, 2024; Patil Akshay R. et al., 2024). Countries that are heavily reliant on traditional meat production for exports may face economic implications due to the rise of cultured meat production and the parallel to a shift in the consumer acceptance towards alternative meat sources. This shift could potentially lead to a scenario, where cultured meat starts replacing a substantial portion of traditional meat products (Chriki & Hocquette, 2020). In countries like Brazil, where the importance of attributes for consumers to switch from conventional beef to cultured meat is being analyzed, cultured meat is seen as a solution to environmental and ethical issues linked to traditional meat production (de Oliveira et al., 2021). Furthermore, a study highlights that the rapid growth of the alternative meat market, including cultured meat, poses a threat to the conventional meat market (Hwang et al., 2020). This threat is further supported by the projection that bioprinting of meat alternatives, which may require less time for cultivation after manufacturing as a high-throughput production system could constitute a significant portion of consumed meat products in the future. As consumer acceptance and market share of cultured meat increases, traditional meat exporters may need to adapt to this changing landscape to maintain their competitiveness.

The introduction of lab-grown meat and sea food to the customers has the potential to significantly impact the food economy. Consumer acceptance and attitudes towards the lab-grown muscle food can be influenced by factors such as regulations, social perceptions like religious, taste and branding comparing to traditional productions (Verbeke et al., 2015; Wilks & Phillips, 2017). According to some studies, the framing and naming of lab-grown muscle food can affect costumer perceptions and willingness to try the products (Bryant & Barnett, 2020; Padilha et al., 2021; Asioli et al., 2022).

7. Future Prospects and Conclusion

3D bioprinting of lab-grown meat shows potential for food technologies, however it is still at an early stage due to the various challenges such as regulation, scalability, acceptance, and high cost for widespread adoption. In addition to these challenges, it requires edible and printable scaffold compositions of non-animal origin (Ianovici et al., 2022). These requirements align with the advancements in scaffold design and need to be developed in parallel related to high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. Another aspect that requires careful consideration is the continuous supply of cells and tissues obtained through biopsy procedures from animals (Mateti et al., 2022) as invaluable resources for uninterrupted production, research and enabling further investigations. To achieve this goal, large-scale cell mass production for industrial applications requires specialized bioreactor systems to efficiently meet pre- and post-production requirements.

Currently, several bioreactor designs are available for mass production of reproducible cells, primarily adapted from biomedical and biotechnology manufacturing fields for meeting the demands of various industries such as pharmaceuticals, biotechnology, and food production (Jossen et al., 2018). In order for this field to fully reach its full potential, efficient cell expansion models must be initially employed then advanced bioreactor systems must be developed for mixing the cells with bioinks and cultivation of the final product. Large-scale cell production systems adopt specialized bioreactors that can accommodate individual cells in suspension or cell aggregates, particularly for adherent cells (Bellani et al., 2020). While selecting production systems and bioreactors for culturing adherent cells and biomaterials, increasing surface area with using microcarriers is crucial for enhancing cellular growth and maturation (Bodiou et al., 2020). Ensuring uniform distribution of nutrients supports the cell viability and proliferation within the bioreactor. Creating the smart systems that are using advanced bioreactor technologies and provide metabolic support while minimizing damaging shear-stress forces (Zhang et al., 2017) would maintain control over the content of the cultured lab grown meat products. Since the microcarrier materials that hold the cell aggregates together can be edible (Yen et al., 2023).

The need for comprehensive automation systems is crucial when optimizing these large-scale productions (Kemmer et al., 2018). Although the initial high costs associated with integrated automation systems may lead the manufacturers to postpone the installation of these systems, it should be viewed as an economic necessity, anticipating long-term cost reductions and operational efficiencies. Expanding cells with smart systems, mixing them with bioinks at desired ratios, and transferring to downstream bioprinters operated by artificial intelligence (AI) in a reasonable time not only increases the power of mass production, but also paves the way for customized artificial meats tailored to specific nutritional requirements.

The challenge of establishing a balanced diet that meets daily nutritional needs, including suitable proportions of protein, fat, and carbohydrates, as well as addressing deficiencies in essential mineral and vitamins, is a topic of discussion in the context of today’s diet. If professional athletes are used as an example, daily nutrition requirements calculated accurately suit their personal needs and maintain overall performance and health. Artificial intelligence-driven systems further offer opportunities to enhance personalized nutrition recommendations and dietary planning (Yang et al., 2021; Hulsen, 2023). By leveraging scientific advancements and evidence-based guidelines, personalized nutrition plans would promote better health outcomes while providing meat products free from possible contaminants or heavy metals from animals. The processing of biomaterials and cells into lab-grown meat, which is planned to be on relatively large scale, can be initiated as a means of increasing productivity considering delivery time for consumer and industry feasibility. Possible innovations should be also integrated into this system to ensure high speed delivery to customer starting from the order intake. Therefore, the adaptation and utilization of overall innovative biofabrication systems that are expected to achieve economic sustainability, eventually depends on the scalability and predictable cost production.

Despite remarkable progress that has been made in the field, meat bioprinting still faces notable challenges that require further exploration. These include optimizing cell viability and maturation within bioprinted constructs, developing cost-effective and scalable bioprinting techniques, and ensuring the safety and nutritional composition of the final products. The integration of biomimetic electrical and mechanical cues to induce proper muscle function, enhance vascularization for nutrient supply, and waste removal remain as an active area of research. The establishment of robust regulatory frameworks and fostering public acceptance play critical roles in shaping the future of cultured meat that should also encompass some other aspects such as consumer perception, packaging requirements, and policy consideration.

Highlights.

• Addressing demand in lab-grown muscle food and 3D bioprinting approaches

• Technical and nutritional criteria underpinning 3D bioprinting strategies

• Developmental and commercialization challenges associated with bioprinted meat

• Exploring the potential societal and environmental impacts of bioprinted meat

Highlights.

• Addressing the demand and development of 3D food bioprinting.

• Adoption of bioprinting modalities to manufacture lab-grown muscle food.

• Highlighting the challenges faced by researchers and industry practitioners.

• Exploring the potential societal and environmental impacts of bioprinted meat.